Would that not be some astronomically large number of humans? Trillions or even more? DNA is huge and there are a lot of different combinations that would vaguely resemble Homo sapiens.

I feel like this concept hinges upon the assumption that genetics determine a person, which is not true. In my opinion, it's more important to raise people in all kinds of environments than to have every genetic individual in existence. Two genetically different individuals raised in an identical situation would likely behave similarly.